Locking chuck

ABSTRACT

A chuck including a body with a nose section defining an axial bore formed therein, a plurality of jaws movably disposed with respect to the body, and a sleeve rotatably mounted about the body so that rotation of the sleeve moves the jaws relative to the axial bore. A bearing has a first race, a second race, and at least one bearing element disposed therebetween, one of the first race and the second race defining a ratchet and the other defining a pawl biased toward the ratchet. A biasing element is disposed between the pawl and the sleeve. The biasing element exerts a biasing force on the pawl toward the ratchet and the ratchet and the pawl prevent the second race from rotating in the opening direction with respect to the first race when engaged.

This application is a continuation of U.S. patent application Ser. No.12/772,413, filed May 3, 2010, which is a continuation of U.S. patentapplication Ser. No. 11/435,405, filed May 17, 2006, entitled “LockingChuck”, now U.S. Pat. No. 7,708,288, which claims priority to U.S.Provisional Application No. 60/682,615, filed May 18, 2005, the entiredisclosures of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates generally to chucks for use with drills orwith electric or pneumatic power drivers. More particularly, the presentinvention relates to a chuck of the keyless type which may be tightenedor loosened by hand or actuation of the driver motor.

Both hand and electric or pneumatic tool drivers are well known.Although twist drills are the most common tools on such drivers, thetools may also comprise screw drivers, nut drivers, burrs, mountedgrinding stones, and other cutting or abrading tools. Since the toolshanks may be of varying diameter or of polygonal cross section, thedevice is usually provided with a chuck adjustable over a relativelywide range. The chuck may be attached to the driver by a threaded ortapered bore.

A variety of chucks have been developed in the art. In an oblique jawedchuck, a chuck body includes three passageways disposed approximately120° apart from each other. The passageways are configured so that theircenter lines meet at a point along the chuck axis forward of the chuck.The passageways constrain three jaws which are movable in thepassageways to grip a cylindrical or polygonal tool shank displacedapproximately along the chuck center axis. The chuck includes a nut thatrotates about the chuck center and that engages threads on the jaws sothat rotation of the nut moves the jaws in either direction within thepassageways. The body is attached onto the drive shaft of a driver andis configured so that rotation of the body in one direction with respectto the nut forces the jaws into gripping relationship with the toolshank, while rotation in the opposite direction releases the grippingrelationship. The chuck may be keyless if it is rotated by hand.Examples of such chucks are disclosed in U.S. Pat. Nos. 5,125,673 and5,193,824, the entire disclosures of which are incorporated by referenceherein. Various configurations of keyless chucks are known in the artand are desirable for a variety of applications.

SUMMARY OF THE INVENTION

The present invention recognizes and addresses the foregoingconsiderations, and others, of prior art constructions and methods.

An embodiment of the present invention includes a chuck for use with amanual or powered driver having a rotatable drive shaft. The chuckincludes a generally cylindrical body having a nose section and a tailsection, the tail section being configured to rotate with the driveshaft and the nose section having an axial bore formed therein. Aplurality of jaws are movably disposed with respect to said body incommunication with said axial bore. A sleeve is rotatably mounted aboutthe body in operative communication with the jaws so that rotation ofthe sleeve in a closing direction moves the jaws toward a longitudinalaxis of the axial bore and rotation of the sleeve in an openingdirection moves the jaws away from the longitudinal axis. A bearing hasa first race adjacent the body, a second race adjacent the sleeve and atleast one bearing element disposed between the first race and the secondrace. One of the first race and the second race define a ratchet and theother of the first race and the second race defines a pawl biased towardthe ratchet, and a biasing element disposed between the pawl and thesleeve. The biasing element exerts a biasing force on said pawl towardsaid ratchet and wherein said ratchet and said pawl are configured sothat when said pawl engages said ratchet, said ratchet and pawl preventsaid second race from rotating in said opening direction with respect tosaid first race.

Another embodiment of the invention provides a chuck for use with amanual or powered driver having a rotatable drive shaft. The chuckincludes a generally cylindrical body having a nose section and a tailsection, the tail section being configured to rotate with the driveshaft and the nose section having an axial bore formed therein. Aplurality of passageways are formed therethrough and intersect the axialbore. A plurality of jaws are movably disposed in said passageways. Agenerally cylindrical first sleeve is rotatably mounted about the bodyand in operative communication with the jaws so that rotation of thefirst sleeve in a closing direction moves the jaws toward a longitudinalaxis of the axial bore and rotation of the first sleeve in an openingdirection moves the jaws away from the longitudinal axis. A bearing hasa first race adjacent the body, a second race adjacent the first sleeveand a plurality of bearing elements disposed between the first race andthe second race. The first race defines a ratchet, the second racedefines a deflectable first pawl biased toward the ratchet, the ratchetand the first pawl being configured so that when the first pawl engagesthe ratchet, the ratchet and first pawl permit the second race to rotatein the closing direction with respect to the first race but prevent thesecond race from rotating in the opening direction with respect to thefirst race. A biasing element is disposed between the second race andthe first sleeve, and the biasing element is configured to bias thefirst pawl toward said ratchet.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate one or more embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof to one of ordinary skill in the art, is set forth moreparticularly in the remainder of the specification, which makesreference to the accompanying figures, in which:

FIG. 1 is a longitudinal view, partly in section, of a prior art chuck;

FIG. 2 is an exploded view of a chuck as shown in FIG. 1;

FIG. 3 is an exploded view of the bearing and nut of the chuck as shownin FIG. 1;

FIG. 4A is a partial perspective view of the sleeve of the chuck asshown in FIG. 1;

FIG. 4B is a partial perspective view of the bearing and sleeve of thechuck as shown in FIG. 1;

FIG. 4C is a partial perspective view of the bearing and sleeve of thechuck as shown in FIG. 1;

FIG. 5 is a perspective view of a chuck jaw of the chuck as shown inFIG. 1;

FIG. 6 is an exploded view of a chuck in accordance with an embodimentof the present invention;

FIG. 7 is a longitudinal view, in section, of a chuck as shown in FIG.6; and

FIG. 8 is an exploded view of a chuck in accordance with an embodimentof the present invention.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference will now be made in detail to presently preferred embodimentsof the invention, one or more examples of which are illustrated in theaccompanying drawings. Each example is provided by way of explanation ofthe invention, not limitation of the invention. In fact, it will beapparent to those skilled in the art that modifications and variationscan be made in the present invention without departing from the scope orspirit thereof. For instance, features illustrated or described as partof one embodiment may be used on another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of thepresent disclosure.

Referring to FIGS. 1 and 2, a prior art chuck 10 includes a body 14, anut 16, a front sleeve 18, a nose piece 20 and a plurality of jaws 22.Body 14 is generally cylindrical in shape and comprises a nose orforward section 24 and a tail or rearward section 26. Nose section 24has a front face 28 transverse to the longitudinal center axis 30 ofbody 14 and a tapered surface 32 at its forward end. The nose sectiondefines an axial bore 34 that is dimensioned somewhat larger than thelargest tool shank that the tool is designed to accommodate. A threadedbore 36 is formed in tail section 26 and is of a standard size to matewith the drive shaft of a powered or hand driver (not shown). The bores34, 36 may communicate at a central region 38 of body 14. While athreaded bore 36 is illustrated, such bore could be replaced with atapered bore of a standard size to mate with a tapered drive shaft.Furthermore, body 14 may be formed integrally with the drive shaft.

Body 14 defines three passageways 40 to accommodate the three jaws. Eachjaw is separated from the adjacent jaw by an arc of approximately 120°.The axes of passageways 40 and jaws 22 are angled with respect to thechuck center axis 30 such that each passageway axis travels throughaxial bore 34 and intersects axis 30 at a common point ahead of thechuck body. The jaws form a grip that moves radially toward and awayfrom the chuck axis to grip a tool, and each jaw 22 has a tool engagingface 42 generally parallel to the axis of chuck body 14. Threads 44,formed on the jaw's opposite or outer surface, may be constructed in anysuitable type and pitch. As shown in FIG. 5, each jaw 22 may be formedwith a carbide insert 112 pressed into its tool engaging surface.

As illustrated in FIGS. 1 and 2, body 14 includes a thrust ring 46 that,preferably, may be integral with the body. It should be understood,however, that thrust ring 46 and body 14 may be separate components.Thrust ring 46 includes a plurality of jaw guideways 48 formed aroundits circumference to permit retraction of jaws 22 therethrough and alsoincludes a ledge portion 50 to receive a bearing assembly as describedbelow.

Body tail section 26 includes a knurled surface 54 that receives anoptional rear sleeve 12 in a press fit at 55. Rear sleeve 12 could alsobe retained by press fit without knurling, by use of a key or bycrimping, staking, riveting, threading or any other suitable securingmechanism. Further, the chuck may be constructed with a single sleevehaving no rear sleeve.

Nose piece 20 retains nut 16 against forward axial movement. The nosepiece is press fit to body nose section 24. It should be understood,however, that other methods of axially securing the nut on the body maybe used. For example, the nut may be a two-piece nut held on the bodywithin a circumferential groove on the outer circumference of the body.Nose piece 20 may be coated with a non-ferrous metallic coating toprevent rust and to enhance its appearance. Examples of suitablecoatings include zinc or nickel, although it should be appreciated thatany suitable coating could be utilized.

The outer circumferential surface of front sleeve 18 may be knurled ormay be provided with longitudinal ribs 77 or other protrusions to enablethe operator to grip it securely. In like manner, the circumferentialsurface of rear sleeve 12, if employed, may be knurled or ribbed as at79 if desired.

Front sleeve 18 is secured from movement in the forward axial directionby an annular shoulder 91 on nose piece 20. A frustoconical section 95at the rearward end of the nose piece facilitates movement of jaws 22within the chuck.

The front and rear sleeves may be molded or otherwise fabricated from astructural plastic such as polycarbonate, a filled polypropylene, forexample a glass filled polypropylene, or a blend of structural plasticmaterials. Other composite materials such as, for example, graphitefilled polymerics may also be suitable in certain environments. Asshould be appreciated by one skilled in the art, the materials fromwhich the chuck is fabricated will depend on the end use of the chuck.

Nut 16 has threads 56 for mating with jaw threads 44. Nut 16 ispositioned about the body in engagement with the jaw threads so thatwhen the nut is rotated with respect to body 14, the jaws will beadvanced or retracted depending on the nut's rotational direction.

As illustrated in FIG. 3, the nut's forward axial face includes recesses62 that receive respective drive dogs 64 (FIG. 2) extending from theinner surface of front sleeve 18. The angular width of the drive dogs isless than that of the recesses, resulting in a slight range of relativerotational movement, for example between 6° and 10° between the nut andthe front sleeve.

Nut 16 also defines a plurality of grooves formed as flats 68 about thenut's outer circumference. Flats 68 receive respective tabs 70 extendingforward from an inner race 72 of a bearing assembly 74. The engagementof tabs 70 and flats 68 rotationally fix the inner race to the nut,although it should be understood that there may be a slight rotationaltolerance between the two.

Inner race 72 receives a plurality of bearing elements, in this casebearing balls 76, disposed between it and an outer race 78 seated onthrust ring ledge 50 (FIG. 1). Outer race 78 is rotationally fixed tobody 14 by a plurality of tabs 80 received in corresponding grooves 82in the thrust ring ledge. In an embodiment of the invention describedherein, outer race 78 is not rotationally fixed with respect to thethrust ring, and tabs 80 and grooves 82 are therefore omitted. In suchembodiment, outer race 78 can rotate with respect to the body until thejaws close onto a tool shank, at which point rearward force from the nutthrough the bearing gives rise to friction between outer race 78 and thethrust ring that holds the outer race in place rotationally on the body.

Returning to the prior art chuck in FIGS. 1 through 3, outer race 78also includes a ratchet formed by a plurality of sawtooth-shaped teeth84 disposed about the inner circumferential surface of the outer race. Afirst pawl 86 extends from one side of each tab 70. First pawl 86 isbiased radially outward from the inner race, thereby urging a distal end88 of each first pawl 86 towards the outer race ratchet.

Each tooth 84 has a first side with a slope approaching 90° with theperiphery of the outer race. A second side of each tooth 84 has a lesserslope. First pawl 86 is deflectable and is generally disposed inalignment with the slope of the second side. Thus, rotation of innerrace 72 in a closing direction 90 with respect to outer race 78 movesfirst pawl distal ends 88 repeatedly over teeth 84, causing a clickingsound each as end 88 falls against each subsequent tooth second side.This configuration of teeth and first pawls 86, however, prevents theinner race's rotation in an opposite opening direction 92. Applicationof rotational force to the inner race in this direction forces distalends 88 into the steep-sloped first sides of teeth 84. Since pawl 86 isgenerally perpendicular to the first sides, it does not deflect inwardto permit rotation. As discussed below, direction 90 corresponds to thechuck's closing direction, while direction 92 corresponds to the chuck'sopening direction. Accordingly, when pawls 86 engage ratchet teeth 84,the teeth permit the inner race's movement in the chuck's closingdirection 90 but prevent its movement in the opening direction 92.

A second deflectable pawl 94 extends from the other side of each tab 70.Like first pawls 86, each second pawl 94 is biased radially outward.Unlike first pawls 86, however, second pawls 94 do not engage the outerrace ratchet.

First and second pawls 86 and 94 include tabs 96 and 98, respectively,at their distal ends. Referring also to FIG. 4A, an innercircumferential surface of sleeve 18 defines first and second recesses100 and 102. During the chuck's operation, each tab 98 is received inone of these recesses, depending on the sleeve's rotational positionwith respect to the nut as discussed in more detail below. The sleevealso defines a third recess 104 and a cam surface 106. Also depending onthe sleeve's rotational position, each tab 96 is received either by thecam surface or by recess 104. The sleeve includes a pair of recesses100, 102 for each tab 98 and a recess 104 and cam surface 106 for eachtab 96.

FIG. 4C illustrates the disposition of pawls 86 and 94 when sleeve 18 isin a first of two positions with respect to nut 16, while FIG. 4Billustrates these components when the sleeve is in a second positionwith respect to the nut. For ease of illustration, both figures omit thenut. However, referring to FIG. 2 and to the sleeve's second position asshown in FIG. 4B, each drive dog 64 is disposed against or adjacent to aside 108 of the gap 62 in which it is received. Each of the sleeve'srecesses 102 receives a tab 98 of a second pawl 94, and each recess 104receives a tab 96 of a first pawl 86. Accordingly, the distal end 88 ofeach first pawl 86 engages ratchet teeth 84, and inner race 72 canrotate only in direction 90 with respect to outer race 78.

Referring now to FIG. 4C, when front sleeve 18 moves in openingdirection 92 with respect to outer race 78, each tab 98 moves out of itsrecess 102 and into its recess 100, as indicated by arrow 107. Each tab96 rides up and out of its recess 104 onto its cam surface 106, asindicated by arrow 110. As indicated by arrow 113, this pushes eachdeflectable tab 86 radially inward, thereby disengaging distal ends 88from ratchet teeth 84. Thus, the inner race is free to rotate withrespect to the outer race.

As described in more detail below, when sleeve 18 rotates in openingdirection 92 so that the inner race moves from the position shown inFIG. 4B to the position shown in FIG. 4C, drive dogs 64 move withingroove 62 of nut 16 (FIG. 2) so that each drive dog is against orimmediately adjacent to a side 111 of the groove.

In operation and referring to FIGS. 2, 3, 4B and 4C, when the chuck isbetween the fully opened and the fully closed positions, nut grooves 62receive drive dogs 64 so that the drive dogs are adjacent groove sides111. Inner race 72 is disposed with respect to outer race 78 so thattabs 96 and 98 are received by cam surface 106 and recess 100,respectively. That is, sleeve 18 is in the first position with respectto the nut, as shown in FIG. 4C. In this condition, tabs 98 and recesses100 rotationally fix inner race 72 to sleeve 18. Since inner race 72 isrotationally fixed to nut 16 by tabs 70 and flats 68, an operatorrotating sleeve 18 rotationally drives the nut through the bearing'sinner race 72, thereby opening or closing the jaws. When the operatorrotates the sleeve, the bearing inner race and the nut in the closingdirection (indicated by arrow 90 in FIG. 4C) to the point that the jawstighten onto a tool shank, the nut is urged rearward up the jaw threads,thereby pushing the nut against inner race 72, bearing elements 76,outer race 78, and thrust ring 46. The rearward force creates africtional lock between the nut and inner race 72 that further holds theinner race and the nut in place rotationally with respect to the body.

The wedge between the nut threads and jaw threads increasingly resiststhe nut's rotation. When the operator continues to rotate sleeve 18 andthe resistance overcomes the hold provided by tabs 98 in recesses 100,sleeve 18 rotates with respect to nut 16 and inner bearing race 72. Thismoves drive dogs 64 from sides 111 of grooves 62 to sides 108 and pushestabs 98 out of recesses 100 into recesses 102. Simultaneously, camsurfaces 106 rotate away from tabs 96 so that the tabs are released intorecesses 104, thereby engaging distal ends 88 of first pawls 86 withratchet teeth 84, as shown in FIG. 4B. At this point, inner race 72, andtherefore nut 16, is rotationally locked to outer race 78, and thereforebody 14, against rotation in the chuck's opening direction. That is, thenut is rotationally locked to the chuck body in the opening direction.Since the nut's rotation with respect to the body is necessary to openthe chuck, this prevents inadvertent opening during use.

Inner race 72, and therefore nut 16, may, however, still rotate withrespect to outer race 78, and therefore body 14, in the chuck's closingdirection. During such rotation, sleeve 18 drives nut 16 through drivedogs 64 against groove sides 108, as well as through inner race 72. Thiscontinues to tighten the chuck and as described above and produces aclicking sound to notify the operator that the chuck is in a fullytightened position.

To open the chuck, the operator rotates sleeve 18 in opening direction92. Sleeve 18 transfers this torque to inner race 72 at the engagementof tabs 96 and 98 in recesses 104 and 102, respectively. Because pawls86 engage outer race 78, which is rotationally fixed to the body, theinner race cannot rotate with the sleeve. Thus, upon application ofsufficient torque in opening direction 92, sleeve 18 moves with respectto the inner race and the nut. This moves tab 96 back up onto camsurface 106, thereby disengaging first pawl 86 from ratchet teeth 84.Tab 98 moves from second recess 102 into first recess 100, and drivedogs 64 move from sides 108 to sides 111 of grooves 62. Thus, the sleevemoves to its first position with respect to the nut, as shown in FIG.4C, and the inner race and nut are free to rotate with respect to theouter race and chuck body. Accordingly, further rotation of sleeve 18 inthe opening direction moves jaws 22 away from the chuck axis, therebyopening the chuck.

The pawls and ratchet may be formed in any suitable configuration.Furthermore, the chuck may be realized in a variety of configurationswhereby a bearing having a ratchet configuration is disposed between asleeve, for example a nut or other suitable configuration, and the chuckbody. For example, a chuck may include a body, a nut that isrotationally fixed to and axially movable with respect to the body, andan outer sleeve that threadedly engages the nut so that rotation of thesleeve moves the nut axially on the body. The jaws may be axially fixedto the nut and received in body passageways so that the nut's axialmovement drives the jaws towards and away from the chuck's axis. In thisconfiguration, an outer sleeve may be permitted to rotate over a limitedangular distance with respect to a second sleeve. A bearing including aratchet configuration as discussed above may be disposed between thesecond sleeve and the chuck body. Depending on the chuck'sconfiguration, the pawls and ratchet may be interchanged as appropriate.

FIGS. 6 and 7 illustrate an embodiment of a chuck 11 of the presentinvention having a body 14, a nut 16, a front sleeve 18 (comprised of ametal outer part 19, a polymer inner part 21 and a metal insert 17), anose piece 20 and a plurality of jaws 22. An embodiment shown in FIG. 8has a front sleeve 18 comprised of a metal outer part 19 and a polymerinner part 21 without a metal insert. Body 14, which is constructedsubstantially the same as the body described above with respect to FIG.2, is generally cylindrical in shape and comprises a nose or forwardsection 24 and a tail or rearward section 26. Nose section 24 has aforward end 32 that tapers from a smooth cylindrical outer circumferenceto a front face transverse to the longitudinal center axis of body 14.The nose section defines an axial bore 34 that is dimensioned somewhatlarger than the largest tool shank the tool is designed to accommodate.A threaded bore 36 is formed in tail section 26 and is of a standardsize to mate with the drive shaft of a powered or hand driver (notshown). Front bore 34 and rear bore 36 may communicate at a centralregion 38 of body 14. While a threaded bore 36 is illustrated, such borecould be replaced with a tapered bore of a standard size to mate with atapered drive shaft. Furthermore, body 14 may be formed integrally withthe drive shaft. A rear ring 37 is also formed integrally with body 14and defines a plurality of guideways 39 to accommodate jaws 22 in theirrearward positions.

Body 14 defines three passageways 40 to accommodate the three jaws. Eachjaw is separated from the adjacent jaw by an arc of approximately 120°.The axes of the jaw passageways and jaws 22 are angled with respect tothe chuck center axis such that each passageway axis travels through theforward axial bore in the body and intersects the chuck axis at a commonpoint. The jaws form a grip that moves radially toward and away from thechuck axis to grip a tool, and each jaw 22 has a tool engaging face 42generally parallel to the axis of chuck body 14. Threads 44, formed oneach jaw's opposite or outer surface, may be constructed in any suitabletype and pitch. As also indicated in FIG. 5, each jaw 22 may be formedwith one or more carbide inserts 112 pressed into its tool engagingsurface.

As illustrated in FIGS. 6 through 8, body 14 includes a thrust ring 46that, in a preferred embodiment, may be integral with the body. Itshould be understood, however, that thrust ring 46 and body 14 may beseparate components. Thrust ring 46 includes a plurality of jawguideways 48 formed around its circumference to permit retraction ofjaws 22 therethrough and includes a ledge portion 50 to receive abearing assembly as described below.

Body tail section 26 includes a knurled surface 54 that receives a dustcover 13 in a press fit. Dust cover 13 could also be retained by pressfit without knurling, by use of a key or by crimping, staking, riveting,threading or any other suitable securing mechanism. Further, the chuckmay be constructed with two hand-actuatable sleeves, as shown in FIGS. 1and 2. Nose piece 20 is press fit to body nose section 24 and retainsnut 16 against forward axial movement. Nose piece 20 may be coated witha non-ferrous metallic coating to prevent rust and to enhance itsappearance. Examples of suitable coatings include zinc or nickel,although it should be appreciated that any suitable coating could beutilized. It should also be understood that other methods of axiallysecuring the nut on the body may be used. For example, the nut may be atwo-piece nut held on the body within a circumferential groove on thebody's outer circumference.

Front sleeve 18 is secured from movement in the forward axial directionby an annular shoulder 91 on nose piece 20. A frustoconical section 95at the rearward end of the nose piece facilitates movement of jaws 22within the chuck.

The outer circumferential surface of front sleeve outer part 19 mayknurled or may be provided with longitudinal ribs or other protrusionsto enable the operator to grip it securely. Outer front sleeve part 19and metal insert 17 (FIGS. 6 and 7) may be deep drawn or otherwisefabricated from steel or other metal material such as Zamac (zincaluminum metal alloy casting). The metal insert is preferably steelhardened to an HRC 43-51. Inner sleeve part 21 may be molded orotherwise fabricated from a structural plastic such as polycarbonate, afilled polypropylene, for example a glass filled polypropylene, or ablend of structural plastic materials. Other composite materials suchas, for example, graphite filled polymerics may also be suitable incertain environments. Metal insert 17 may be pressed or otherwiseassembled inside inner sleeve part 21 in close conformity so that theinner sleeve part retains the metal insert. In one preferred embodiment,inner sleeve part 21 is molded about the metal insert. As should beappreciated by one skilled in the art, the materials from which thechuck of the present invention is fabricated will depend upon the enduse of the chuck, and the above materials are provided by way of exampleonly.

Generally, the outer surface of inner part 21 conforms to the innersurface of outer part 19. However, polymer inner part 21 defines aplurality of flanges 23 that extend forward from the main portion of theinner sleeve part. Flanges 23 include front edges 25 that extendradially outward to thereby define a groove 27 between edges 25 and thefront edge of the inner sleeve part's main portion. The segmentedarrangement of flanges 23 allows the flanges to flex inward as the outerpart is assembled over the inner part. A front edge 29 of outer sleevepart 19 extends radially inward and is notched to receive flanges 23.Thus, at the notches, front edge 29 extends radially inward into groove27, while flanges 23 extend through the notches. Thus, groove 27 retainsouter sleeve part 19 in the axially forward and rearward directionsbetween the tabs' front edges 25 and the forward edge of the mainportion of sleeve inner part 21. Sleeve outer part 19 rotationallydrives sleeve inner part 21 through the interengagement of front edge 29and flanges 23 and through a plurality of spaced-apart dogs (not shown)extending radially inward from the outer sleeve part's innercircumferential surface into corresponding notches 31 in the front outersurface of inner sleeve part 21. It should be understood that thetwo-part sleeve shown in FIGS. 6 through 8 may be replaced with aunitarily-formed polymer sleeve such as shown in FIGS. 1 and 2.

Nut 16 has threads 56 for mating with jaw threads 44 and is positionedabout the body in engagement with the jaw threads so that when the nutis rotated with respect to body 14, the jaws will be advanced orretracted depending on the nut's rotational direction.

The nut's forward axial face includes recesses 62 that receiverespective drive dogs 64 extending from the inner surface of innersleeve part 21. Recesses 62 and drive dogs 64 are constructed asdescribed above with respect to FIG. 2. Similarly, the inner surface ofmetal insert 17 (or, in the embodiment of FIG. 8, sleeve inner part 21)defines recesses 100, 102 and 104 and a cam surface 106 as is describedabove with respect to the inner surface of sleeve 18 in FIGS. 1 and 2.For the purpose of clarity, the positions of recesses 100, 102 and 104and cam surface 106 in inner sleeve part 21 behind insert 17 areindicated in FIG. 6 as recesses 100 a, 102 a, and 104 a, and cam surface106 a.

Nut 16 also defines a plurality of grooves, formed as flats 68 about thenut's outer circumference, that receive respective tabs 70 extendingforward from an inner race 72 of a bearing assembly 74. The engagementof tabs 70 and flats 68 rotationally fix the inner race to the nut,although it should be understood that there may be a slight rotationaltolerance between the two.

Inner race 72 receives a plurality of bearing elements, in this casebearing balls 76, disposed between it and an outer race 78 seated onthrust ring ledge 50. Outer race 78 is rotationally fixed to body 14 bya plurality of tabs 80 received in corresponding grooves 82 in thethrust ring ledge, as is described above with respect to FIGS. 1 and 2.In an alternate embodiment, outer race 78 is not rotationally fixed withrespect to the thrust ring, and the tabs and grooves are thereforeomitted. In such alternate embodiment, outer race 78 can rotate withrespect to the body until the jaws close onto a tool shank, at whichpoint rearward force from the nut through the bearing gives rise tofriction between outer race 78 and thrust ring ledge 50 that ultimatelyholds the outer race in place rotationally on the body.

As discussed above with respect to outer race 78 in FIG. 2, outer races78 in FIGS. 6 through 8 include a ratchet. In the illustratedembodiments, the ratchet is formed by a plurality of saw tooth-shapedteeth 84 disposed about the outer race's inner circumferential surface.A first pawl 86 extends from one side of each tab 70 and is biasedradially outward from the inner race, thereby urging a distal end 88 ofeach first pawl 86 toward the outer race ratchet. Teeth 84 are formed,and interact with pawl distal end 88, as described above with respect tothe corresponding components of FIGS. 1 through 4.

A second deflectable pawl 94 extends from the other side of each tab 70.Like first pawls 86, each second pawl 94 is biased radially outward.Unlike first pawls 86, second pawls 94 do not engage the outer raceratchet. Pawls 86 and 94 are constructed identically to pawls 86 and 94as described above with respect to FIGS. 1 and 2. First and second pawls86 and 94 include tabs 96 and 98, respectively, at their distal endsthat interact with recesses 100, 102 and 104, and cam surface 106, inthe same manner as described above. Moreover, the operation of thechucks shown in FIGS. 6 through 8, with respect to opening, closing andlocking by the interaction of pawls 86 and 94 with the inner surface ofsleeve 18 (more particularly, the inner surface of metal insert 17 inFIGS. 6 and 7 and inner sleeve part 21 in FIG. 8), is the same as theoperation of chuck 10 shown in FIGS. 1 through 4, and is therefore notrepeated.

In drill chuck 10 as shown in FIGS. 1 and 2, nut 16 defines a smoothcylindrical shoulder 130 extending in the axial direction between acurved surface 132 and a transverse annular shoulder 134 extendingbetween shoulder 130 and an annular shoulder 136 upon which flats 68 aredefined. In the embodiments of the present invention illustrated inFIGS. 6 through 8, a resilient structure is disposed between shoulder130 and first and second pawls 86 and 94 in sufficient volume and/orgeometry so that the resilient intermediate structure increases thepawls' radially outward bias to thereby dampen vibrations that arisefrom the chucks' usage with a given power driver and that otherwise tendto dislodge the pawls from their positions with respect to the outerrace and sleeve, as shown in FIGS. 4B and 4C.

As shown in FIGS. 6 through 8, for example, a groove 138 is formed inshoulder 130 so that, when nut 16 is assembled onto body 14, groove 138is defined in a plane perpendicular to the chuck axis and receives anO-ring 140. In one preferred embodiment, O-ring 140 is made of VITON, afluoroelastomer manufactured by DuPont Dow Elastomers LLC of Wilmington,Del., and has an axial width of about 1/16 inches, an inner diameter ofabout 1.000 inches and an outer diameter of about 1.125 inches.

The diameter defined by shoulder 130 on either side of groove 138 isapproximately 1.244 inches, while the diameter of a circle defined bythe trough of groove 138 is approximately 1.200 inches. Thus, O-ring 140stretches when installed into groove 138, and its outer diameter becomesapproximately 1.325 inches. A radius defined from the axis of chuck body14 to any of pawls 86 and 94 in their positions as shown in FIG. 4B isapproximately 0.651 inches, corresponding to a diameter of 1.302 inches.First and second pawls 86 and 94 thereby compress O-ring 140, which, dueto its resilience, responsively applies a radially outward force to thepawls. This radially outward force provides a secondary radially outwardbias to the pawls that supplements the pawls' inherent radially outwardbias and increases the pawls' tendency to remain seated in either oftheir two above-described positions during the power driver's operation.That is, O-ring 140 increases resistance to vibrational forces that maytend to push the pawls radially inward out of their respective groovesdefined in the inner diameter of the sleeve, thereby inhibiting thechuck from opening or closing during use.

It will also be recognized that the increased radially outward biasincreases the force necessary to be applied by the user in moving thesleeve between the locking mechanism's two operative positions. Thus, itshould be understood that the materials and geometry of O-ring 140 maybe selected to dampen vibrations in a power driver having a given powerrating while still permitting effective manual operation by the user.For example, it is expected that a drill chuck as described above withrespect to FIGS. 6 through 8 (where O-ring 140 has a Shore A hardnessfrom 60 to 80 and where outer race 78 is rotationally fixed to body 14by tabs 80 received in grooves 82 in the thrust ring) will resistvibrations generated by a model GSB 18-2 RE 750 watt AC impact drill,manufactured by BOSCH Tool Corporation of Farmington Hills, Mich., suchthat the chuck does not undesirably open or over tighten.

In another preferred embodiment, groove 138 is formed into shoulder 130in a square cross section, and O-ring 140 is formed in a correspondinglysquare cross section. The dimensions of the nut and O-ring otherwiseremain the same.

It should also be understood that various materials may be used toconstruct O-ring 140. For example, materials include various suitableelastomers such as acrylonitrile-butadiene (NBR, buna N, or nitrilerubber), chloroprene rubber (CR, or neoprene), polyacrilic rubber,silicone rubber, butyl rubber (ITR), styrene-butadiene (SBR, or buna Srubber), chlorosulfonated polyethelene (CSM, commercially availableunder the name HYPALON), or polysulfide rubber (T, or thiokol polymer)or thermoplastics such as suitable fluorocarbons (e.g. Teflon TFE orFEP), impact grade polystyrenes comprising polystyrene and rubber, andpolyamide resins (nylon). O-rings made from commercially availablematerials such as the fluoroelastomers and perfluoroelastomers VITON,KALREZ, SIMRIZ, CHEMRAZ and AFLAS, and HYPALON (chlorosulfonatedpolyethylene), are available from Marco Rubber & Plastic Products, Inc.of North Andover, Mass.

The shape of O-ring 140 may vary as desired. For example, O-ring 140maybe molded into a shape that conforms at its inner diameter to theouter surface of shoulder 130 (with or without a groove 138) and thatconforms at its outer circumference to the surfaces of pawls 86 and 94that face the nut. The molded O-ring is preferably made by compressionmolding and can be formed from any of the above-described materialssuitable for compression or injection molding. The O-ring can be moldedas a separate component or can be molded directly around the nut.

To determine whether a given dampening structure, whether an O-ring of aselected material and geometry or any other selected resilient device,will sufficiently dampen vibrations for a given chuck configuration on agiven driver, the structure may be assembled on a chuck and tested withthe driver. Referring to the drill chuck as shown in FIGS. 6 through 8,for example, the chuck may be assembled and operated with a drill bitshank so that jaws 22 securely grip the tool shank. An alignment mark isthen made axially along the outer surface of sleeve 18, nose piece 20and the tool shank so that the mark lies on the sleeve, nose piece andtool shank in a plane that includes the axis of chuck body 14. Thedriver/chuck/bit is then operated to drill holes in selected materials,for example steel, concrete, diorite and wood. A hammer function may beapplied while drilling in concrete and diorite. After each hole isdrilled, or after each of a certain number of holes is drilled, thealignment of the marks on the sleeve, nose piece and bit is checked todetermine whether the chuck has undesirably opened or over tightened.

The construction of the pawls and ratchet teeth contribute to theresistance of the locking mechanism to vibrations and, consequently, tothe degree to which a supplemental outward bias is desirable. Forexample, the depth of pawl teeth 84 constructed as described abovecontributes to the effectiveness of the primary outward bias and, in apreferred embodiment as shown in FIGS. 6 through 8, is approximately14/1000 inches. Further, pawls 86 and 94 are preferably constructed withsufficient stiffness so that when the inner and outer races areassembled together on the nut (but apart from the chuck body and jaws),and the nut and inner race are rotationally secured, at least an about 2in-lb torque is required to ratchet pawl end 88 over teeth 84, and in apreferred embodiment, the torque required is within a range of about 2to about 3 in-lbs. In the example described below in which an about 0.7gram layer of RTV sealant is disposed between the nut and the pawls, thetorque required to ratchet the pawl over the ratchet teeth is within arange of about 4 in-lbs to 5 in-lbs.

It should also be understood that mechanisms other than O-rings may beused to apply additional bias to the pawls. In another preferredembodiment, for example, groove 138 in shoulder 130 may be omitted, sothat shoulder 130 has a smooth surface as in FIGS. 1 and 2, and a springband is received over the shoulder. The spring band is comprised of acentral annular ring that may fit loosely over or be pressed to shoulder130. A number of spring arms extend outward from, and are biasedradially away from, the central band. There is one spring arm for eachpawl 86 and 94, and a distal end of each spring arm engages itscorresponding pawl to thereby apply a supplemental radially outward biasto the pawl. Particularly where the spring band's central ring fitsloosely about the nut, the distal end of each spring arm may define tabsshaped correspondingly to tabs 96 and 98 (see FIG. 3) so that the springarm tabs are received in tabs 96 and 98 to thereby rotationally orientthe spring band with respect to inner race 72.

In a further preferred embodiment, shoulder 130 is again smooth, andO-ring 140 is replaced by a layer of silicone RTV (room-temperaturevulcanized) rubber, for example 732 multi-purpose silicone RTV sealantmade by Dow Corning Corporation and available from IDG Corporation ofBelmont, N.C. The RTV sealant may be applied manually or automatically.For a construction as shown in FIGS. 6 through 8, in which six pawls 86and 94 are used, six nozzles may be arranged in a pattern so that whenthe nozzles are brought to a position proximate shoulder 130, thenozzles deposit dots of RTV sealant at positions on the shouldercorresponding to the opposing pawls.

In a preferred embodiment in which shoulder 130 defines a diameter ofapproximately 1.244 inches, a total of approximately 0.7 grams of RTVsealant is disposed on the shoulder. It should be understood, however,that the amount of RTV sealant may vary as desired, with the lower endof the desirable range being the point at which the RTV sealant fails toprovide sufficient resilient force for a given chuck and driver, and theupper end of the desirable range being the point at which RTV sealantextends beyond an operative space between shoulder 130 and the pawls andthereby fails to contribute to the additional bias force. In thearrangement (with a smooth shoulder 130) as described above with respectto FIGS. 1 and 2, a range of 0.4 grams to 1.6 grams was found to bedesirable. Using a chuck as in FIGS. 6 through 8 with the methoddescribed above, a 0.7 gram layer of RTV sealant was found to dampenvibrations in a model GSB 18-2 RE 750 watt AC impact drill and a modelGSB 20-2 RCE 1010 watt AC impact drill manufactured by BOSCH ToolCorporation of Farmington Hills, Mich.

While one or more preferred embodiments of the present invention havebeen described above, it should be understood that any and allequivalent realizations of the present invention are included within thescope and spirit thereof. Thus, the depicted embodiments are presentedby way of example only and are not intended as limitations on thepresent invention. It should be understood that aspects of the variousone or more embodiments may be interchanged both in whole or in part.Therefore, it is contemplated that any and all such embodiments areincluded in the present invention as may be fall within the literal orequivalent scope of the present disclosure.

1. A chuck for use with a manual or powered driver having a rotatabledrive shaft, said chuck comprising: a generally cylindrical body havinga nose section and a tail section, said tail section being configured torotate with said drive shaft and said nose section having an axial boreformed therein; a plurality of jaws movably disposed with respect tosaid body in communication with said axial bore; a sleeve rotatablymounted about said body in operative communication with said jaws sothat rotation of said sleeve in a closing direction moves said jawstoward a longitudinal axis of said axial bore and rotation of saidsleeve in an opening direction moves said jaws away from saidlongitudinal axis; a bearing having a first race adjacent said body, asecond race adjacent said sleeve and at least one bearing elementdisposed between said first race and said second race, one of said firstrace and said second race defining a ratchet and the other of said firstrace and said second race defining a pawl biased toward said ratchet;and a biasing element disposed between the pawl and the sleeve, whereinsaid biasing element exerts a biasing force on said pawl toward saidratchet and wherein said ratchet and said pawl are configured so thatwhen said pawl engages said ratchet, said ratchet and said pawl preventsaid second race from rotating in said opening direction with respect tosaid first race.
 2. The chuck as in claim 1, wherein said biasingelement further comprises an O-ring.
 3. The chuck as in claim 2, whereinsaid biasing element lies in a plane that is transverse to saidlongitudinal axis of said axial bore.
 4. The chuck as in claim 2,wherein said sleeve includes a first sleeve and a second sleeve andwherein said first sleeve rotationally drives said second sleeve but ismovable with respect to said second sleeve between a first position anda second position.
 5. The chuck as in claim 4, wherein said O-ring has acircular cross-section.
 6. The chuck as in claim 4, wherein said O-ringhas a rectangular cross-section.
 7. The chuck as in claim 4, whereinsaid second sleeve further includes an annular groove configured toreceive said O-ring.
 8. The chuck as in claim 4, wherein a surface ofsaid O-ring adjacent said pawl has a complimentary shape to that of saidpawl.
 9. The chuck as in claim 4, wherein said first sleeve defines acam surface disposed with respect to said pawl so that said cam surfacedisengages said pawl from said ratchet when said first sleeve is in saidfirst position with respect to said second sleeve and releases said pawlto engage said ratchet when said first sleeve is in said second positionwith respect to said second sleeve.
 10. The chuck as in claim 1, whereinsaid sleeve is an annular nut having threads formed thereon inengagement with threads on said jaws so that rotation of said nut aboutsaid body moves said jaws toward or away from said longitudinal axis.11. A chuck for use with a manual or powered driver having a rotatabledrive shaft, said chuck comprising: a generally cylindrical body havinga nose section and a tail section, said tail section being configured torotate with said drive shaft and said nose section having an axial boreformed therein and a plurality of passageways formed therethrough andintersecting said axial bore; a plurality of jaws movably disposed insaid passageways; a generally cylindrical first sleeve rotatably mountedabout said body and in operative communication with said jaws so thatrotation of said first sleeve in a closing direction moves said jawstoward a longitudinal axis of said axial bore and rotation of said firstsleeve in an opening direction moves said jaws away from saidlongitudinal axis; and a bearing having a first race adjacent said body,a second race adjacent said first sleeve and a plurality of bearingelements disposed between said first race and said second race, saidfirst race defining a ratchet, said second race defining a deflectablefirst pawl biased toward said ratchet, said ratchet and said first pawlbeing configured so that when said first pawl engages said ratchet, saidratchet and said first pawl permit said second race to rotate in saidclosing direction with respect to said first race but prevent saidsecond race from rotating in said opening direction with respect to saidfirst race, and a biasing element disposed between said second race andsaid first sleeve, wherein said biasing element is configured to biassaid first pawl toward said ratchet.
 12. The chuck as in claim 11,wherein said first sleeve further comprises a nut.
 13. The chuck as inclaim 12, further comprising a second sleeve that is in operativecommunication with said nut so that said second sleeve rotationallydrives said nut but is rotatable with respect to said nut between afirst rotational position and a second rotational position.
 14. Thechuck as in claim 13, wherein said second sleeve defines a cam surfacedisposed with respect to said first pawl so that said cam surfacedisengages said first pawl from said ratchet when said second sleeve isin said first position with respect to said nut and releases said firstpawl to engage said ratchet when said second sleeve is in said secondposition with respect to said nut.
 15. The chuck as in claim 11, whereinsaid biasing element further comprises an O-ring.
 16. The chuck as inclaim 15, wherein said O-ring has a circular cross-section.
 17. Thechuck as in claim 15, wherein said nut further includes an annulargroove formed in an outer surface and said O-ring is received therein.